Fixes #1307.

Allow Esri for_storage to be set on a per call basis

(Don't set globally.)

Fixes #1059.

by making all class methods public. Previously a call to #near or
within_bounding_box produced:

  DEPRECATION WARNING: Delegating missing full_column_name method to
  Venue. Accessibility of private/protected class methods in :scope is
  deprecated and will be removed in Rails 6.0.

I don't like turning all these methods public but at the moment I don't
see any way around it.

Make Nominatim the default lookup and map provider.

Closes #1026.

viz: add `coordinates` attribute and remove `latitude` and `longitude`.

Fixes #1258 and #1302.

Add error details for Google lookup

OpenCage website URLs have changed

Culprits: .present? and .try

Appears to be defunct.

Fixes #609. Bing seems to support this type of character escaping now.
It's not discussed in their documentation but it works with every query
I've tried so hopefully we're finally good on this issue.

Also remove some unnecessary assertions from tests.